Several methods of cooling and liquefying a hydrocarbon stream such as natural gas stream are known. It is desirable to liquefy natural gas stream for a number of reasons. As an example, natural gas can be stored and transported over long distances more readily as a liquid than in gaseous form, because it occupies a smaller volume and does not need to be stored at high pressures.
An example of a method for liquefying natural gas is described in U.S. Pat. No. 6,370,910.
Although the method according to U.S. Pat. No. 6,370,910 already give satisfying results, it has been found that if the natural gas provided is at temperatures significantly differing from the temperature of the refrigerants, thermal stresses due to differential expansions and internal pinches may occur in the cooling equipment. This problem may even be more pertinent during the winter months and/or in cold areas such as the Arctic region as a result of which the natural gas is provided at relative low temperatures.
Apart from equipment related problems, the above may result in a lower thermal efficiency for the cooling or liquefaction process.
It is an object of the present invention to minimize one or more of the above problems.
It is a further object of the present invention to provide an alternative method for cooling, in particular liquefying, a hydrocarbon stream.